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Wednesday, September 24, 2008

Survivor: theoretical physics

Some very interesting data here on jobs in particle theory, cosmology, string theory and gravity over the last 15 years in the US (1994 -- present).

Based on these numbers and the quality of the talent pool I would guess theoretical physics is the most competitive field in academia, by a large margin. (Your luck will be much, much better in computer science, engineering, biology, ...)

The average number of years between completing the PhD and first faculty job is between 5-6. That would make the typical new assistant professor about 33, and almost 40 by the time they receive tenure.

This is over 15 years, so that means even at the top three schools only 1 or at most 2 PhDs from a typical year gets a job in the US. The US is by far the most competitive market. If you follow the link you will see that the list of PhD institutions of US faculty members is truly international, including Tokyo, Berlin, Moscow, etc. (Note I think the jobs data also includes positions at Canadian research universities, so I should have written N. America rather than US.)

The field is very much dominated by the top departments; the next most successful include MIT, Stanford, Caltech, Chicago, etc.

Here are some well-known schools that only produced 1 professor of theoretical physics over 15 years: UCLA, UC Davis, U Illinois, U Virginia, U Arizona, Boston University, U Penn, Northwestern, Moscow State University (top university in USSR), Insitute for Nuclear Research (INR) Moscow

You can see that by the time we reach 3 professors produced over 15 years we are talking about very, very good physics departments. Even many of the schools in the 1 and 2 category are extremely good. These schools have all hired multiple professors over 15 years, but the people hired tend to have been produced by the very top departments. The flow is from the top down.

This dataset describes a very big talent pool -- I would guess that a top 50 department (in the world) produces 3-5 PhDs a year in theoretical physics. If most of them only place a student every 5 years or so, that means a huge number (the vast majority) of highly trained, even brilliant, physics students end up doing something else!

How many professors do you think are / were straight with their PhD students about the odds of survival?

I only knew one professor at Berkeley who had kept records and knew the odds. One day in the theory lounge at LBNL Mahiko Suzuki (PhD, University of Tokyo) told me and some other shocked grad students and postdocs that about 1 in 4 theory PhDs from Berkeley would get permanent positions. His estimate was remarkably accurate.

How many professors do you think had / have a serious discussion with their students about alternative career paths?

How many have even a vague understanding of what the vast majority of their former students do in finance, silicon valley, ...?

"How many have even a vague understanding of what people who leave theoretical physics do in finance, silicon valley, ...?"

Amen. A personal goal over the past few years for me has been to at least make some contact into these fields and also to gain some understanding of what non-academia physics Ph.D.s end up doing. I was reminded of this recently when I visited my old advisor at Caltech and he was discussing many of his contacts into a diverse array of "real world" companies. Okay, well he may be an exception, but certainly he's a good model.

In my freshman year at MIT, Alan Guth told me not to count on ever reaching tenure, but to study physics anyway if that's what interested me. I was a bit skeptical - after all, he had gotten to MIT on the basis of one half-baked cosmological model -- but you can't say I wasn't warned.

A very vague understanding is exactly what they have. At least in my experience, that vague understanding did not translate to anything usefull when it actually came to finding a job. It's like they hear some stories of ex-physicists done good in the real world, and that's just enough to assuage any feelings of guilt they may have.

Big deal, they spend a few years doing something fun and then get a real job. Beats having to deal with boring clients, spreadsheets, and office politics for a few years. Why do people think every graduate degree has to be useful for a career? I do agree that the situation should be better known than it is, so people can prepare for alternative careers if it comes to that.

The data is wrong, I know people from other universities which have landed jobs, which are not shown whatsoever. But the idea is there, that we know. Nothing new, is the grad student's responsibility also to figure that out, don't blame all on the advisor! Grad students are mature enough to figure it out... grad school is not kindergarten :)

I would guess that is true -- but remember we are talking about professors at research universities in the US (i.e., doesn't count people who ended up professors in other countries or at teaching colleges).

I think it is also true of quite a few other departments in the US. Keep in mind places like UCLA, etc. (which are much bigger departments) have produced 1.

When you say research universities.. keep in mind there is no distinct boundary between research university and non-research university. But more significantly, I don't think teaching at a place like Amherst necessarily counts as not being a physicist. In math at least there are those who continue doing research at those places, and some of them are quite good.

Brian: Oops, I forgot that one of Rudy's students is now in the nuclear theory group at LBNL. So UO has at least produced one theoretician with a permanent position -- I don't know if this is covered in the data because he is in QCD / nuclear theory.

The statistics cited here refer to High Energy Physics Only. That is not all of physics. In fact, that is a very small part of physics, hence the very small numbers of hires. If, for one, you included Theoretical Solid State physics (the largest branch of physics) the numbers would look a little better. But imho not good enough to encourage a young person to go into physics. Finally, imho things like cosmology and string theory, which have no connection to experiments, hardly qualify as physics anyway. But that is just my humble opinion.

I would be cautious about drawing too many conclusions from such scant and ill-defined data, though there can be no doubt that competition for the "best" positions in hep-th is fierce. It would be very interesting to see a more complete description, perhaps something similar to that available for mathematics:

http://www.ams.org/employment/surveyreports.html

That said, I certainly believe that advisors should be frank with students regarding career options and prospects. I was fortunate to have such an advisor. However, based upon purely anecdotal evidence, it seems that much of the time there is no discussion regarding various possibilities, and certainly little consideration given to whatever objectives the student may have.

More generally, I wonder in how many departments are the questions "Where do we want our students to end up in 10 years?", "Is this realistic?", and "Is our program set up to accomplish this?" even asked.

Any idea what the statistics for Rutgers or UCSB are like? Rutgers had a string of postdocs who did very well: Juan Maldacena, Matt Strassler, Dan Kabat and Hong Liu are examples. But, I don't know about the graduate students there, except for Lubos Motl and Gabadadze (at NYU).

You ask "How many professors do you think are / were straight with their PhD students about the odds of survival?"

Obviously, if a student directly asks about this, a professor should not lie.

However, I wonder whether to what extent people feel that professors should go out of their way to make this information clear up front. Should I post a sign on my door: "WARNING: If you work for me, there is only a 1% chance you'll stay in academia" ?

None of my current students have asked me about their "odds of survival" (my honest answer to them would have to be "zero", anyway). I don't even know whether they want to stay in academia. If they are interested in theoretical physics, and hard working, then I do not care about their motivation for getting a Ph.D. Is this wrong?

Why are you comparing theoretical physics to all of biology or all of computer science? Try comparing theoretical computer science with theoretical physics -- I'd be interested to see the data on that.

1) There's a fine line between making sure your students are making an informed decision and actively discouraging them from doing theory. I would put it this way: suppose your college age daughter were considering a career in field X, with which you little familiarity. What level of information would you like *her* to have about it?

2) I'm not that familiar with the prospects in theoretical CS. Perhaps you can tell me, at the programs ranked 10-20, are the odds less than 1 in 10 for someone to find a research job in the US? If not, then HET is worse.

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I am not sure why we still producing many many many Ph.D. to compete for very few positions, shouldn't we limit the number of Ph.D. students so that the current senior theorists don't have to go Silicon Valley or Wall Street to find a job?